Fig. 4.

Other drug–receptor pairs follow the same binding pathway. (A) Bound pose of propranolol (purple), superimposed on the carazolol–β₂AR crystal structure (PDB entry 2RH1, gray) (data from simulation 15). (B) Distance to binding pocket (ligand nitrogen atom to Asp^3.32 C_γ) and ligand hydration for propranolol and isoproterenol binding to β₂AR, and for alprenolol binding to β₁AR (data from simulations 13, 16, and 21). The insets illustrate a typical extracellular-vestibule-bound state for each simulation.